_base_ = './config_a.py'           # _base_ = ['./config_a.py', './config_e.py']
c = (1, 2)
d = 'string'
f = dict(_delete_=True, b2=None, b3=0.1)  # 所有在b中的旧键 b1, b2, b3 将会被新键 b2, b3 所取代。
e = dict(b2=1)
"""
>>> from mmcv import Config
>>> cfg = Config.fromfile('config_b.py')
>>> cfg
Config (path: config_b.py): {'a': 'config_a.py', 'b': 'mmcv_study/Config/config_a', 'c': (1, 2), 'd': 'string', 'f': {'b2': None, 'b3': 0.1}, 'e': {'b2': 1}}
"""